Shading coil



y 1930. L. c. FRANK 1,768,950

SHADING COIL Filed Jan. 30, 1950 Fig. I.

,4 Fig. 3.

INVENTOR Leo 0. Frank.

ATTORNEY Fateeted duly 1, 1938 LEO G. FRANK, OF MCKEESPORT, PENNSYLVANIA, ASSIGNQR {BRIG &; MANUFACTURING COMPANY,

ESTINGHGHSE ELEG- A CORPORATIGN PENNSYLVANIA SHADEII (30111 Application filed January 30, Serial 4%,570.

lily invention relates generally to shading coils for alternating-current magnets.

The use of shading coils in connection with elcctroinagnets, which are energized by alternating current, to reduce chattering of the arinatures is old in the art, the theory of operation is well known and Will not be descr bed in detail.

lrleretotore, a great'deal of trouble has been. exocrienced With shading coils becom inc; loose and breaking as a result of the impact oi the armature striking the core when the magnet is actuated. This impact and also the heating of the armature causes the laminations of the arn'iature to spread. apart or expand. ,Vhen shading coils are used. on. the magnets of contactors for industrial service, which operate almost constantly, this action produces strains on the coils which cause them to break. a

An object of my invention is to provide a shading coil which may be economically manutactured and readilv assembled by a machine operation.

.A more specific object of my invention is to provide a shading coil that shallhe resilient and may be distorted. slightly in shape to permit expansion of the magnetic conductor on which it may be mounted Without subjecting the members of the coil to disrupting strains.

also object of my invention to faoili re moon of the shadin soil by n1.

. o invention, reference she d detailed descicot-ion. with the accretion hich: s View, partly in e elevation, oi an electr n coils, constructed in on, mounted t ll, 9. portion only of which is shown.

trated magnet comprises a magnetizahle core 10 of U-shape which is supported by a frame An armature is supported by an arm 13 which is pivotally mounted on the frame 11 by a pin 14.

In order to ellect the operation of the arniature 12, a coil 15 is mounted on one leg of the core 10, d When the coil 15 is excited from a source of alternating current, the core member 19 is energized and deenergized cyclically. The energization of the magnet effects the actuat tion of the armature 12 into engagement with the core member 10, hereby establishing a closed magnetic circuit.

In order to prevent chattering, which is caused by the varying flux, shading coils 16 are mounted on the armature 12. In this par ticular instance, the shading coils are made from sections of seamless tubing, usually of brass or copper, but it will be readily understood that any other suitable non-magnetic conductor may be utilized. A section of tubing so shaped to constitute an elongated link having side members 17 and recnti'ant end portions 18 for engaging the armature 19). A coil. constructed in this manner is resilient and may be distorted slightly in snaps.

vi 1 "f llie cestoniaiy slots l3 ale fjlOi ltl cl in s shown in 3, f r rece1vr Y J", m

ie S(.illl; coll. in. assen e coils are Yd departing from the spirit and scope of the inventlon, 1t 15 desired that the foregoing description be construed as illustrative and not in a limiting sense.

I claim as my invention:

1. A shading coil for the armature of an alternating-current magnet comprising an elongated link member of conducting material for mounting on the armature, said link member having its ends curved inwardly to present faces for resiliently engaging the armature to permit expansion of the latter Without imposing suiiieient strains on the link member to break it.

2. A shading coil for an alternating-current-magnet core comprising a link member of conducting material for mounting on the core, said link member having portions extending inwardly to provide resilient projections to engage the core.

3. A shading coil for a magnetic conductor comprising a link member for mounting on the conductor, said link member being curved inwardly to present a face to resiliently engage the conductor to permit a predetermined expansion of the conductor Without exerting sufficient strains to break the link.

4. A shading coil for a. magnetic conductor comprising a link of conducting material having a reentrant portion disposed to resiliently engage the magnetic conductor and to permit a predetermined expansion of the conductor Without exerting disrupting strains on the link.

5. A shading coil for a magnetic conductor comprising a link of conducting material having a plurality of reentrant portions disposed to resiliently engage the conductor and to permit a-predetermined expansion of the conductor withoutexerting disrupting strains on the'link.

6. A shading coil for a magnetic conductor comprising a section of seamless tubing so shaped as to constitute an elongated link for mounting on the conductor, said link having portions curved inwardly to resilientl; engage the conductor and to permit a predetermined expansion of the conductor Without producing suiiicient strains on the link to break it.

7. A shading coil for a magnetic conductor comprising a section of tubing having a substantially rectangular shape for mounting on the conductor, said section having portions curved inwardly to resiliently engage the conductor and to permit a predetermined expansion of the conductor without breaking the section of tubing.

In testimony whereof, i have hereunto subscribed my name this Qlst day of January,

LEO C. FRANK. 

